• 关键词：磷  胡敏酸  酶水解  元素组成  核磁共振

• 基金项目：国家重点研发计划项目（No.2017YFD0300608，2017YFD0200205）；国家自然科学基金（No.41471196）

• 孙元宏
• 吉林农业大学资源与环境学院, 吉林省商品粮基地土壤资源可持续利用重点实验室, 长春 130118

• 李翠兰
• 吉林农业大学资源与环境学院, 吉林省商品粮基地土壤资源可持续利用重点实验室, 长春 130118

• 张晋京
• 吉林农业大学资源与环境学院, 吉林省商品粮基地土壤资源可持续利用重点实验室, 长春 130118

• 摘要：磷（P）是存在于腐殖物质中的主要元素之一，然而不同来源腐殖物质中P素的生物有效性及其影响因素尚不清楚.本研究以土壤、泥炭、玉米秸秆、牛粪、猪粪和鸡粪为供试材料，利用酶水解方法比较了不同来源胡敏酸（HA）中P素生物有效性的差异，分析了P素生物有效性与HA化学组成之间的关系.结果发现：HA中活性无机P占HA全P的19.9%~46.4%，活性有机P占HA全P的23.3%~53.8%，活性P总量占HA全P的43.3%~84.7%；活性有机P中，类植酸态P的比例（9.13%~25.1%）最高，其次为简单单酯P（7.06%~22.3%）和多核苷酸P（4.12%~7.46%）；不同来源HA相比，活性无机P的含量以土壤HA最高而鸡粪HA最低，活性有机P的含量以秸秆HA最高而牛粪HA最低，活性P总量的顺序为秸秆HA > 土壤HA ≈ 猪粪HA > 泥炭HA > 牛粪HA > 鸡粪HA；Pearson线性相关分析指出，活性无机P与Al含量之间呈显著的负相关，活性有机P与Ca、Mg、Zn、碳水化合物和双烷氧碳含量之间呈显著的正相关，而活性P总量与Fe含量之间呈显著的负相关.上述结果说明，不同来源HA结合态P素的生物有效性不同，其中秸秆HA结合态P素的生物有效性最高，其次为土壤HA、猪粪HA、泥炭HA和牛粪HA，而鸡粪HA结合态P素的生物有效性最低；HA中酶可水解的活性有机P含量与其中金属元素和有机碳官能团的组成有关，HA中与Ca、Mg和Zn结合的P是酶可水解的有机P形态，同时HA中活性有机碳官能团含量较高则活性有机P的含量也较高.

• Abstract：Phosphorus (P) is one of the major elements in humic substances. However, the bioavailability and influencing factors of P associated with humic substances from different sources are still unclear. In this study, humic acids (HA) were isolated from soil, peat, maize straw, and livestock manures (i.e., cattle manure, pig manure, and chicken manure). The differences of the bioavailability of P associated HA were compared by using enzymatic hydrolysis experiments. Moreover, the correlations between P bioavailability and chemical compositions of HA were explored. The labile inorganic P, labile organic P, and total labile P accounted for 19.9%~46.4%, 23.3%~53.8%, and 43.3%~84.7% of total P in HA, respectively. In the labile organic P, phytate-like P displayed the highest proportion (9.13%~25.1%), followed by simple monoester P (7.06%~22.3%) and polynucleotide P (4.12%~7.46%). Among HA from the different sources, the labile inorganic P content was highest in HA from soil and lowest in HA from chicken manure, while the labile organic P content was highest in HA from maize straw and lowest in HA from cattle manure. The total labile P content in HA from different sources was in the order maize straw > soil ≈ pig manure > peat > cattle manure > chicken manure. Pearson correlation analysis shows that the labile inorganic P was negatively correlated with Al content, the labile organic P was positively correlated with Ca, Mg, Zn, carbohydrate C, and di-O-alkyl C, whereas the total labile P was negatively correlated with Fe content in HA. The above results suggest that the bioavailability of P associated with HA from different sources was distinct, in which the bioavailability of P is the highest for HA from maize straw, followed by HA from soil, pig manure, peat and cattle manure, and the lowest is for HA from chicken manure. The Ca-, Mg-, and Zn-bound P in HA are enzyme hydrolysable organic P forms, and the labile organic P is high in HA with high labile organic C functional groups.

• Key words：phosphorus  humic acid  enzymatic hydrolysis  elemental composition  nuclear magnetic resonance

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